Decay Simulator: Thorium-208
General data
| Element name | Thorium |
|---|---|
| Chemical symbol | Th |
| Atomic number Z | 90 |
| Isotope name (symbol) | Thorium-208 (Th-208) |
| Neutron number N | 118 |
| Mass number A=Z+N | 208 |
Interactive radioactive decay simulation of Thorium-208: atom-by-atom decay, full decay chain, charts of nuclei count and activity.
| Half-life | 3.1 ms |
|---|
Radioactive decay series
- Thorium-208 3.1 ms
- Radium-204 58 ms
- Radon-200 1.03 s
- Polonium-196 5.63 s · 86.0%
- Lead-192 3.5 min · 80.8%
- Astatine-200 43 s · 14.0%
- Bismuth-196 5.13 min · 12.6%
- Thallium-192 9.6 min · 80.8%
- Polonium-200 11.5 min · 6.6%
- Lead-196 37 min · 13.3%
- Mercury-192 4.85 h · 80.8%
- Gold-192 4.94 h · 80.8%
- Platinum-192 stable · 80.8%
- Thallium-196 1.84 h · 13.3%
- Mercury-196 stable · 13.3%
- Bismuth-200 36.4 min · 5.8%
- Lead-200 21.5 h · 5.8%
- Thallium-200 26.1 h · 5.8%
- Mercury-200 stable · 5.8%
Rare branches (below 0.01%)
Rare branches are transformations that occur in fewer than 0.01% of decays, e.g. double beta decay or cluster emission. The nuclides they produce are practically absent from a sample, so they are hidden by default to keep the main path clear. In this series: branches - 1, nuclides - 12.
- Mercury-188 3.25 min · 0.0048%
- Gold-188 8.84 min · 0.0048%
- Platinum-188 10.2 d · 0.0048%
- Iridium-188 41.5 h · 0.0048%
- Osmium-188 stable · 0.0048%
- Platinum-184 17.3 min · 1.8×10⁻⁹%
- Iridium-184 3.09 h · 1.8×10⁻⁹%
- Osmium-184 1.12×10¹³ a · 3.0×10⁻⁹%
- Osmium-180 21.5 min · 3.0×10⁻¹⁴%
- Rhenium-180 2.46 min · 3.0×10⁻¹⁴%
- Tungsten-180 1.59×10¹⁸ a · 3.0×10⁻⁹%
- Hafnium-176 stable · 3.0×10⁻⁹%
How to read the simulation
Grid: each pixel is one atom of the starting isotope. When an atom decays, the pixel takes the colour of the decay product - in decay series mode the product can decay further. The moment each atom decays is random, but the probability follows from the half-life, so after one T½ about half of the atoms remain, after two - about a quarter.
Chart N(t): what percentage of the sample atoms each nuclide makes up at a given moment. The line of the starting isotope falls (by half after each T½), the lines of stable products rise, and those of short-lived ones first rise, then fall.
Chart A(t): activity, i.e. the number of decays per second (becquerel, Bq). It depends on the number of atoms and on how fast they decay: for the same number of atoms, the shorter the T½, the higher the activity.
Simulation time runs faster (or slower) than real time - the time scale slider sets the multiplier. This way you can watch the decay of isotopes that live from fractions of a second to billions of years.
Well-known isotopes
- H-3 - Tritium - glowing watch hands, nuclear fusion fuel.
- C-14 - Radiocarbon dating.
- K-40 - Natural radioactivity - in bananas and in our bodies.
- Co-60 - Radiotherapy and radiation sterilization.
- I-131 - Thyroid treatment; Chernobyl fallout.
- Cs-137 - Long-lasting contamination after Chernobyl and Fukushima.
- Rn-222 - Radon in basements and mines.
- Ra-226 - The longest-lived isotope of radium - the element discovered by Marie and Pierre Curie in 1898.
- U-235 - Nuclear power plant fuel; start of the actinium series.
- U-238 - Age of the Earth; start of the uranium series.
- Pu-238 - Power source for space probes (Voyager, Curiosity rover).
- Am-241 - Ionization smoke detectors.
Data sources
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain